Bath tubs with side doors that can be lifted up to a storage position above the main tub section are commercially available. These bath tubs function well and are found in many hospitals and nursing homes. The overhead door storage requires overhead storage space, a track system to guide and support the door, and a lift system to lift the door to the storage position. These bath tubs require more space than is available in most home bathrooms. They are also too large to be moved into existing home bathrooms even if the bathroom is large enough to house the tub and door assembly. The track system and the door lift systems add substantial complexity and cost to the bath tub units.
Bath tubs with side doors that are hinged to a main tub section have been known for many years. Hinged doors often provide limited access to a tub, require an elaborate latching system and, in at least some cases, leak. The force exerted against a bath tub side door depends upon the depth of the water and the surface area of the door in contact with the water. Hinged bath tub doors generally have a reduced area to limit the total force applied against the doors. It is also common for the doors to have a bottom edge that is above the bottom wall to further reduce the total force applied against the door. Reduced door size impedes bath tub ingress and egress and renders such bath tubs unusable by some individuals. A space for a hinged door to swing outwardly away from the main portion of a tub during opening and closing must be provided. The door must have room to move into a position in which it does not block movement of a bather who is moving to or from the tub. Hinged doors compress door seals, slide along the surface of portions of seals, and may rotate on the surface of a portion of a door seal. Sliding contact with untreated seals causes seal wear and may lead to leaks.
Bath tubs with side doors that slide up and down have been proposed. Such doors may be difficult to open and close and require special sealing systems to prevent leaks. Operation of levers and cams that are part of the sealing system may require substantial dexterity.